AttributeError raising while executing "repository sync" with cache

[Jun Omae]

trac-admin repository sync ​libgit2 with cache fails.

2014-12-05 17:10:57,798 Trac[git_fs] INFO: Trying to sync revision [39cd01779c84e0574c11f2e804f28c815e82a583]
2014-12-05 17:10:57,838 Trac[console] ERROR: Exception in trac-admin command:
Traceback (most recent call last):
  File "trac/admin/console.py", line 108, in onecmd
    rv = cmd.Cmd.onecmd(self, line) or 0
  File "/usr/lib/python2.6/cmd.py", line 218, in onecmd
    return self.default(line)
  File "trac/admin/console.py", line 276, in default
    return cmd_mgr.execute_command(*args)
  File "/home/jun66j5/src/tracdev/git/trac/admin/api.py", line 124, in execute_command
    return f(*fargs)
  File "/home/jun66j5/src/tracdev/git/trac/versioncontrol/admin.py", line 157, in _do_sync
    self._sync(reponame, rev, clean=False)
  File "/home/jun66j5/src/tracdev/git/trac/versioncontrol/admin.py", line 140, in _sync
    repos.sync(self._sync_feedback, clean=clean)
  File "/home/jun66j5/src/tracpygit2plugin/trunk/tracext/pygit2/git_fs.py", line 257, in sync
    @self.env.with_transaction()
  File "/home/jun66j5/src/tracdev/git/trac/db/api.py", line 77, in transaction_wrapper
    fn(ldb)
  File "/home/jun66j5/src/tracpygit2plugin/trunk/tracext/pygit2/git_fs.py", line 260, in do_insert
    self._insert_cset(db, rev, cset)
  File "/home/jun66j5/src/tracpygit2plugin/trunk/tracext/pygit2/git_fs.py", line 359, in _insert_cset
    for path, kind, action, bpath, brev in cset.get_changes():
  File "/home/jun66j5/src/tracpygit2plugin/trunk/tracext/pygit2/git_fs.py", line 1443, in get_changes
    files = self.repos._get_changes(parent.tree, commit.tree)
  File "/home/jun66j5/src/tracpygit2plugin/trunk/tracext/pygit2/git_fs.py", line 888, in _get_changes
    for git_object, name in _walk_tree(self.git_repos, parent_tree):
  File "/home/jun66j5/src/tracpygit2plugin/trunk/tracext/pygit2/git_fs.py", line 421, in _walk_tree
    for val in _walk_tree(repos, git_object, name):
  File "/home/jun66j5/src/tracpygit2plugin/trunk/tracext/pygit2/git_fs.py", line 420, in _walk_tree
    if git_object.type == GIT_OBJ_TREE:
AttributeError: 'NoneType' object has no attribute 'type'

[Jun Omae]

In 14297:

TracPygit2Plugin: fixed sync crashing when non-existent entry is iterated by tree object (closes #12093)